Electronic device generating finger images at a progressively slower capture rate and related methods

Abstract

An electronic device may include finger biometric sensing pixels and a processor capable of cooperating with the finger biometric sensing pixels to generate a series of finger images at a progressively slower capture rate as a finger settling increases over time from initial placement of a user's finger adjacent the finger biometric sensing pixels. The processor may also be capable of cooperating with the finger biometric sensing pixels to determine a quality factor for each image in the series thereof, and select at least one image from the series thereof for matching and based upon the quality factor.

That which is claimed is: 
     
       1. An electronic device comprising:
 a plurality of finger biometric sensing pixels; and 
 a processor arranged to cooperate with the plurality of finger biometric sensing pixels to
 generate a series of finger images at a progressively slower rate as finger settling increases over time during static placement of a user's finger adjacent the plurality of finger biometric sensing pixels, 
 determine a quality factor for each image in the series thereof, and 
 select at least one image from the series thereof for matching for authentication and based upon the quality factor. 
 
 
     
     
       2. The electronic device of  claim 1  wherein the processor cooperates with the plurality of finger biometric sensing pixels to generate the series of finger images at the progressively slower rate by at least
 capturing the series of finger images as finger settling increases over time at a constant rate; and 
 processing the captured series of finger images at the progressively slower rate. 
 
     
     
       3. The electronic device of  claim 1  wherein the processor generates the series of finger images, determines the quality factor, and selects the at least one image from the series thereof for matching in a matching mode; and wherein the processor cooperates with the plurality of finger biometric sensing pixels in an enrollment mode to
 generate a series of finger images at a constant rate as finger settling increases over time from an initial static placement of a user's finger adjacent the plurality of finger biometric sensing pixels; 
 determine a quality factor for each image in the series thereof; and 
 select at least one image from the series thereof for enrollment based upon the quality factor. 
 
     
     
       4. The electronic device of  claim 1  wherein the processor comprises:
 processing circuitry integrated with the plurality of finger biometric sensing pixels; and 
 a host processor coupled to the processing circuitry. 
 
     
     
       5. The electronic device of  claim 4  wherein the processing circuitry is arranged to generate a wakeup signal to switch the host processor from a low power sleep mode to an awake mode. 
     
     
       6. The electronic device of  claim 5  wherein the processing circuitry comprises at least one frame buffer arranged to store earliest ones of the series of finger images prior to the host processor switching to the awake mode. 
     
     
       7. The electronic device of  claim 1  wherein the processor is arranged to determine the quality factor for each image based upon deformation of the user's finger. 
     
     
       8. The electronic device of  claim 1  wherein the processor is arranged to determine the quality factor for each image based upon at least one of contrast, a histogram shape, and smoothness. 
     
     
       9. The electronic device of  claim 1  wherein the processor is arranged to determine the quality factor for each image based upon at least one of a threshold amount of energy at a given ridge frequency and an image transform. 
     
     
       10. The electronic device of  claim 1  wherein the processor is arranged to determine the quality factor for each image in the series thereof based upon at least one of a ridge-flow vector matrix, a vector strength, and an entropy. 
     
     
       11. The electronic device of  claim 1  wherein the processor is arranged to determine the quality factor for each image based upon a region of each image in the series thereof. 
     
     
       12. The electronic device of  claim 1  wherein the processor is arranged to average pixel values based upon the series of finger images. 
     
     
       13. The electronic device of  claim 1  wherein the plurality of finger biometric sensing pixels comprises electric field finger biometric sensing pixels. 
     
     
       14. The electronic device of  claim 1  wherein the processor is arranged to select a plurality of images from the series thereof for matching and based upon the quality factor. 
     
     
       15. An electronic device comprising:
 a housing; 
 a finger operated user input device carried by the housing; 
 a plurality of finger biometric sensing pixels carried by the finger operated user input device; and 
 a processor carried by the housing and arranged to cooperate with the plurality of finger biometric sensing pixels to
 generate a series of finger images at a progressively slower rate as a finger settling increases over time during static placement of a user's finger adjacent the plurality of finger biometric sensing pixels, 
 determine a quality factor for each image in the series thereof, and 
 select at least one image from the series thereof for matching for authentication and based upon the quality factor. 
 
 
     
     
       16. The electronic device of  claim 15  wherein the processor cooperates with the plurality of finger biometric sensing pixels to generate the series of finger images at the progressively slower rate by at least
 capturing the series of finger images as finger settling increases over time at a constant rate; and 
 processing the captured series of finger images at the progressively slower rate. 
 
     
     
       17. The electronic device of  claim 15  wherein the processor generates the series of finger images, determines the quality factor, and selects the at least one image from the series thereof for matching in a matching mode; and wherein the processor cooperates with the plurality of finger biometric sensing pixels in an enrollment mode to
 generate a series of finger images at a constant rate as finger settling increases over time from an initial static placement of a user's finger adjacent the plurality of finger biometric sensing pixels; 
 determine a quality factor for each image in the series thereof; and 
 select at least one image from the series thereof for enrollment based upon the quality factor. 
 
     
     
       18. The electronic device of  claim 15  wherein the processor comprises:
 processing circuitry integrated with the plurality of finger biometric sensing pixels; and 
 a host processor coupled to the processing circuitry. 
 
     
     
       19. The electronic device of  claim 18  wherein the processing circuitry is arranged to generate a wakeup signal to switch the host processor from a low power sleep mode to an awake mode. 
     
     
       20. The electronic device of  claim 19  wherein the processing circuitry comprises at least one frame buffer arranged to store earliest ones of the series of finger images prior to the host processor switching to the awake mode. 
     
     
       21. The electronic device of  claim 15  wherein the finger operated input device comprises a pushbutton switch. 
     
     
       22. The electronic device of  claim 15  further comprising wireless communications circuitry carried by the housing; and wherein the processor is arranged to cooperate with the wireless communications circuitry to perform at least one wireless communications function. 
     
     
       23. A method of matching a finger biometric using an electronic device that includes a plurality of finger biometric sensing pixels and a processor capable of cooperating with the plurality of finger biometric sensing pixels, the method comprising:
 using the processor to
 generate a series of finger images at a progressively slower rate as a finger settling increases over time during static placement of a user's finger adjacent the plurality of finger biometric sensing pixels, 
 determine a quality factor for each image in the series thereof, and 
 select at least one image from the series thereof for matching for authentication and based upon the quality factor. 
 
 
     
     
       24. The method of  claim 23  wherein the processor is used to generate the series of finger images at the progressively slower rate by at least
 capturing the series of finger images as finger settling increases over time at a constant rate; and 
 processing the captured series of finger images at the progressively slower rate. 
 
     
     
       25. The method of  claim 23  wherein the processor is used to generate the series of finger images, determine the quality factor, and select the at least one image from the series thereof for matching in a matching mode; and wherein the processor is used in an enrollment mode to
 generate a series of finger images at a constant rate as finger settling increases over time from an initial static placement of a user's finger adjacent the plurality of finger biometric sensing pixels; 
 determine a quality factor for each image in the series thereof; and 
 select at least one image from the series thereof for enrollment based upon the quality factor. 
 
     
     
       26. The method of  claim 23  wherein the processor comprises processing circuitry integrated with the plurality of finger biometric sensing pixels and a host processor coupled to the processing circuitry; and wherein the processing circuitry generates a wakeup signal to switch the host processor from a low power sleep mode to an awake mode. 
     
     
       27. The method of  claim 23  wherein the processor determines the quality factor for each image based upon deformation of the user's finger. 
     
     
       28. The method of  claim 23  wherein the processor determines the quality factor for each image based upon at least one of contrast, a histogram shape, and smoothness. 
     
     
       29. The method of  claim 23  wherein the processor determines the quality factor for each image based upon at least one of a threshold amount of energy at a given ridge frequency and an image transform. 
     
     
       30. The method of  claim 23  wherein the processor determines the quality factor for each image in the series thereof based upon at least one of a ridge-flow vector matrix, a vector strength, and an entropy.